An annular bi-directional clutch includes an inner race, an outer race and a cage disposed between the inner and outer race. The cage includes a plurality of circumferentially spaced openings which receive rollers. The rollers selectively engage both the inner and outer race. As the inner race rotates from a neutral or rest position into an engaged or driving position the rollers are forced to ride up corresponding flats formed on the inner race by a resisting cage. Each roller is then trapped between the inner and outer race and torque is transmitted between the inner and outer races. As the clutch disengages the inertia of the rollers and cage tends to provide the force required to move the cage from the engaged to neutral position such that the rollers no longer engage both the inner and outer race. However, the inertial force of the rollers is often insufficient. Therefore, the clutch may not disengage, returning the cage back to its neutral position with respect to the inner race.
The prior art teaches the use of various methods to prevent rotation between a cage and an inner race. For example, a stop in the form of a peg may extend from a cavity formed in an outer periphery of the inner race into the sides of a split resilient cage. The resilient cage effects frictional engagement with the outer race before wedging means such as rollers come into action, to oppose the centrifugal forces associated with the wedging means, and to retain the wedging means in position. Alternatively, a spring loaded wedge may be used which simultaneously engages mutually inclined ends of the split cage. However, in the case of the spring loaded wedge, the rigid structure of the wedge is received in the cavity of the inner race and between the split cage ends. Thus, the spring loaded wedge functions in a manner parallel to the stop, preventing rotation between the cage and inner race, but permitting the cage to radially expand and contract.
There is also a teaching in the prior art of placing a spring between an input shaft and an output shaft to urge cam members disposed between them into a neutral position. However, such a usage is inapplicable to an overrunning clutch, wherein an outer race must be able to rotate relative to an inner race.